The Environment (ENV) module calculates wheel-to-tank fuel consumption and emissions for each vehicle type. The key variables in this calculation are fuel consumption or fuel intensity, and emission factors or emission index. These factors are divided into technologies that are represented in the model by the age cohort or vintage.
The module produces estimates of CO2 emissions and five other pollutants: CO, VOC, NOx, SO2 and PM2.5. Fuel consumption and emissions are calculated per origin country and disaggregated to zones based on the share of transport demand in each zone.
The Environment module receives input from the Passenger and Freight Demand modules and from the Vehicle Stock module (fleet size).
The module comprises two parts (see Figure). Firstly, the predicted transport demand segmented by country, mode and fuel type is disaggregated by vehicle type and vehicle technology (represented by the vehicle age cohort). Secondly, fuel consumption and emissions are derived and calculated for each mode, vehicle type, fuel, and age cohort (technology) using the previously disaggregated transport demand, fuel consumption and emission factors.
Dataset on fuel consumption and emission factors for all vehicle age cohorts (technology) are available for the year 2010. For each period in the remaining simulation period (2015-2050), only factors of the new vehicles (vehicles between 0 and 4 years-old) are available in the dataset. These factors are modifiable to enable policy simulation, such as introduction of new emission standards in a specific time or simulation period.
Fuel consumption by and emission factors of older vehicles (vehicles more than 4 years old) are derived from the dataset for the previous period. For example, fuel consumption factors for 5 year-old vehicles in period (t) equal the fuel consumption factors for new vehicles in period (t-5).